Spread of weed of concern

Otago Peninsula Community Board member Paul Pope examines some of the banana passionfruit plant....
Otago Peninsula Community Board member Paul Pope examines some of the banana passionfruit plant. Photo by Jonathan Chilton-Towle

Many people consider passionfruit a delicacy best served with ice cream or cheesecake but on Otago Peninsula it has become a serious threat to native bush.

The banana passionfruit plant, which has pink flowers and fruit that resembles small egg plants, is a common sight alongside Portobello Rd and it is overwhelming the other plants that grow there.

Otago Peninsula Board member Paul Pope said the peninsula was an important scenic and biologically diverse area, and if not for the passionfruit the roadsides could be home to totara, ngaio and other native plants.

''It's been a problem for years,'' he said.

Mr Pope hoped to see some kind of co-ordinated complementary approach to eradicate the weed. According to the Department of Conservation website, banana passionfruit is a vigorous climber, often growing several metres in height. There are several varieties in the wild and the plant is closely related to the type of passionfruit found in supermarkets.

The banana passionfruit plant was capable of smothering forest margins and forest regrowth with its dense growth of leafy vines, Doc said.

The common methods of controlling the plant are pruning and using herbicides.

Doc partnerships ranger John Barkla said banana passionfruit had long been recognised as a serious weed.

It was particularly hard to deal with because it produced fruit. Birds ate the fruit and dispersed the seeds over a wide area through their droppings.

The department was focused on controlling the plant at ''high-value sites'' but it was too widespread to eliminate everywhere without an enormous concerted effort involving multiple organisations, he said.

''Ideally, we'd do it all but we have limited funds,'' Mr Barkla said.

Save The Otago Peninsula (S.T.O.P) trustee Moira Parker owns a 36ha property on the peninsula with her husband which is under two QEII covenants.

She has a constant battle to keep banana passionfruit off the land.

It was a common sight on Otago Peninsula, especially on the warmer north-facing side. As well as being on the Portobello Rd roadside, the weed had begun to establish itself on small islands in the harbour such as Goat Island and Pudding Island, she said.

S.T.O.P had several re-vegetation projects under way on the peninsula and was constantly vigilant to ensure it did not get into these areas, Mrs Parker said.

- by Jonathan Chilton-Towle 

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